Research On Storage Allocation And Task Scheduling In Shuttle-based Storage And Retrieval System

With the rapid development of the logistics industry,the traditional warehousing model has been unable to meet the growing demand for efficient storage and transportation in the logistics industry.As a new mode of intelligent warehousing,the shuttle truck warehousing system has gradually attracted more and more attention.This kind of three-dimensional warehouse has the characteristics of high space utilization rate and high degree of automation.While improving the efficiency of logistics transportation,it can also effectively reduce costs.The ensuing problem is how to further improve the system efficiency and space utilization without changing the physical conditions of the vertical storage.In this paper,the cargo space allocation and task scheduling problem of the shuttle truck storage system are studied.The main research contents and results are as follows :1.The open-loop queuing network model under the classified storage strategy of the shuttle storage system is established.This paper analyzes the characteristics of common storage strategies,and establishes an open-loop queuing network model under a single operation mode for the purpose of evaluating the throughput changes of the shuttle truck storage system under different demand curves.By changing the shape parameters of the demand curve,the throughput change of a storage system is calculated.The results show that the model can better realize the reservoir division under the classified storage strategy for the turnover rate of inbound goods.2.A multi-objective optimization mathematical model is established to solve the dynamic cargo allocation problem.Based on the basic assumptions of the storage system,the classification storage strategy is used to divide the storage area.Considering the three principles of distance priority,shelf stability and uniform travel,a multiobjective optimization mathematical model is established.Through the penalty function method and the method of removing part of the location number when initializing the population,the possibility of the fast non-dominated genetic algorithm converging to the illegal solution is reduced,and the dynamic location allocation problem under the classified storage strategy can be effectively solved.3.The completion time model of storage task queue with buffer and the improved flower pollination algorithm are proposed.The warehousing process of the cooperative work of the hoist and the shuttle in the shuttle storage system is analyzed,and a completion time model of the warehousing task queue with buffer is proposed.The basic flower pollination algorithm is improved,and a mutation flower pollination algorithm based on simulated annealing mechanism is proposed.The algorithm is verified by test functions and actual task scheduling problems,and the results show good convergence.4.Virtual scheduling verification of task scheduling model based on digital twin system.On the basis of proposing the architecture of intelligent storage digital twin system,a digital twin system for a vertical warehouse is developed.The functions of the system include but are not limited to fault alarm,scheduling simulation,threedimensional visualization,etc.Applying the scheduling simulation function in the system,the task queue completion time model with buffer is verified by virtual scheduling.The results show the effectiveness of the model and the reliability of the virtual scheduling function.